Phthalocyanines

ABSTRACT

IN WHICH Pc is a phthalocyanine residue, the benzene nucleus A is unsubstituted or substituted by at least one alkyl group having up to 4 carbon atoms and n represents a whole number from 1 to 8; phthalocyanine pigment mixtures containing such a compound; process for the stabilisation of phthalocyanine pigments which comprises incorporating therein at least one compound of formula (I); and paints, lacquers, enamels, inks and plastic materials coloured by means of phthalocyanine pigment mixture containing a compound formula (I).   Phthalocyanine compounds of the formula:

United States Patent 1 Kienzle et a1.

Aug. 28, 1973 PHTHALOCYANINES 22 Filed: Nov. 22, 1971 21 Appl. No.:201,202

[30] Foreign Application Priority Data Nov. 20, 1970 France 7041758 {52]U.S. Cl. 106/288 Q, 260/3145 [51] Int. Cl C08h 17/14 [58] Field ofSearch 106/288 Q [56] References Cited UNITED STATES PATENTS 3,646,0032/1972 Lamure 106/288 Q FOREIGN PATENTS OR APPLICATIONS 758,485 5/1967Canada 106/288 Q 949,739 2/1964 Great Britain 106/288 Q PrimaryExaminer.-Delbert E. Gantz Assistant Examiner.lames W. HellwegeAttorney-Francis C. Browne. Joseph A. DeGrandi et al.

[ ABSTRACT Phthalocyanine compounds of the formula:

in which Pcis a phthalocyaninc residue, the benzene nucleus A isunsubstituted or substituted by at least one alkyl group having up to 4carbon atoms and n represents a whole number from 1 to 8; phthalocyaninepigment mixtures containing such a compound; process for thestabilisation of phthalocyanine pigments which comprises incorporatingtherein at least one compound of formula (1); and paints, lacquers,enamels, inks and plastic materials coloured by means of phthalocyaninepigment mixture containing a compound formula (1).

6 Claims, No Drawings PHTHALOCYANINES The invention relates tophthalocyanine compounds and to phthalocyanine pigment mixtures whichare stable towards crystallisation.

It is known that the a form of copper phthalocyanine has the drawback ofcrystallising. The crystallisation or growth of the crystals takes placeslowly in the cold and rapidly in the hot on contact with aromatichydrocarbons. For example, in a paint kept in a can and containing suchsolvents, the micro-crystals of the pigment are slowly changed intolarger crystals with a considerable loss of colouring power. Thisphenomenon constitutes an objection against the use of this substance ininks, paints and plastics. The crystallisation of the a form representsa change into the more stable form. The reduction in the colouring poweris due to the relatively large dimensions of the slowly developedcrystals of B form. In addition, since the B form is greener than the aform, an alteration of shade is observed at the same time.

With the object of making the a form of copper phthalocyaninenon-crystallising, it has been proposed to stabilise it by mixing itwith another metallic phthalocyanine or by coating the particles withcolourless protecting substances. This coating however also involves areduction of colouring power.

It has now been found that the crystallisation can be prevented bymixing the phthalocyanines with a compound of the general formula:

Pc CHS-C [A l- 2 N n (I) in which Pc represents a phthalocyanineresidue, the benzene nucleus A is unsubstituted or substituted by atleast one alkyl group having up to 4 carbon atoms and n represents awhole number from l to 8, preferably 3 or 4.

The phthalocyanine of residue Pc may or may not be metallised. Thephthalocyanine of the residue Pc may be copper phthalocyanine in its aor )3 form or a halogenated derivative thereof, especially a chlorinatedderivative containing up to 4 percent of chlorine.

The compounds of formula (I) may be prepared by reacting achloromethylated derivative of phthalocyanine with aZ-mercapto-benzothiazole, the benzene nucleus of which is unsubstitutedor substituted by at least one alkyl group having up to 4 carbon atoms,using at least the same number of moles of 2-mercaptobenzothiazole asthe number of chloromethyl groups.

The chloromethylated derivatives of phthalocyanine may be obtained byknown processes, for example by condensing a phthalocyanine withsymmetrical dichlorodimethyl ether or with paraformaldehyde in thepresence of aluminium chloride or chlorosulphonic acid. The knownprocesses of halo-methylation usually give mixtures of halo-methylatedderivatives and these mixtures are suitable for preparing the compoundsof formula (I). The reaction is preferably effected in the presence ofan alkaline substance, such as sodium hydroxide or sodium carbonate. Thereaction may be carried out at temperatures between 50 and C. either inan excess of Z-mercapto-benzothiazole or in a solvent. Having regard tothe above-defined reaction conditions, polar solvents, such asisopropanol or ethyl Cellosolve, may be used; only the thiol reacts.("Cellosolve" is a Trade Mark).

The pigment mixtures of the present invention may be advantageouslyprepared by incorporation. The incorporation of compounds of fonnula (I)into the phthalocyanines to be stabilized may be effected in severalways. For example, the compound of formula (I) and the phthalocyanine tobe stabilised may be ground together in the dry state, preferably with agrinding aid such as sodium sulphate. The compound of formula (I) andthe phthalocyanine to be stabilised may be introduced together into asolvent, such as sulphuric acid, and precipitated by the introduction ofthe solution into water while preventing too great a rise intemperature. After precipitation, the pigment mixture is filtered off,washed and dried.

The compound of formula (I) and the phthalocyanine pigment to bestabilised may also be simply admixed in the dry state by agitationwithout the grinding action.

The pigment mixtures of the present invention preferably contain 1 to 20percent of the compound of formula (I), based on the total weight of themixture.

The phthalocyanine pigment mixtures may also be prepared by attachingchloromethyl groups to the phthalocyanine to be stabilised by means ofpartial chloromethylation and then reacting the partly chloromethylatedphthalocyanine with a 2-mercaptobenzothiazole.

The compounds of formula (I), which are soluble in the aromaticsolvents, have the property of not being leached out in the solventswhen they form part of pigment compositions.

The phthalocyanine pigment mixtures of the present invention areparticularly good as colouring materials for paints, lacquers, enamels,printing inks and plastic materials since they are rapidly dispersed innonaqueous media and offer a strong resistance to the growth of thecrystals.

The following Examples, in which the parts are parts by weight,illustrate the invention without restricting it.

EXAMPLE 1 alcohol to eliminate excess mercapto-benzothiazole,

then washed with water and dried. 22.4 parts of tris-(benzothiazolyl-thio-methyl) copper phthalocyanine are obtained.

Analysis: Calculated S: 16.6 percent Found 15.8 percent EXAMPLE 2 25parts of the a form of copper phthalocyanine are mixed with 1 part oftris-(benzothiazolyl-thio-methyl)- copper phthalocyanine (obtained as inExample 1) in 200 parts of water.

This suspension is mixed with 50 parts of glass balls having a diameterof about 0.5 mm in a cylindrical container provided with a centralstirrer having planar discs. After grinding for 30 minutes, the groundsuspension is separated from the grinding elements. The pigment isfiltered off, drained and dried.

Examination of its stability to solvents is determined as follows:

1 g. of pigment mixture is dispersed in 100 ml of xylene, then thedispersion is heated under reflux for 2 hours. After cooling, theproduct is separated by filtration and dried after washing with ethanol.The X-ray diagram shows that 100 percent of a-phthalocyanine is stillpresent in the pigment mixture.

When the pigment mixture is applied in an emulsion paint after treatmentin the xylene, reduction of the colouring power with respect to theuntreated product is not observed.

Under the same conditions the a form of the copper phthalocyanine (asthe pure product) recrystallises completely in the form of large needlesof the )3 form when the benzothiazolylthio-methylated derivative is notpresent. The treatment with xylene in such a case involves a distinctdiminution in the colouring power as compared withthe untreated producton application in emulsion paints.

EXAMPLE 3 If the a form of copper phthalocyanine used in Example 2 isreplaced by a chlorinated phthalocyanine (a form) containing 2.8 percentof the chlorine, a pigment mixture is obtained which resistscrystallisation in so]- vents and which, on application in emulsionpaint, possesses the colouring power of the B pigment before the xylenetreatment.

EXAMPLE 4 1. A phthalocyanine pigment mixture which contains a compoundof the formula:

in which P0 is a phthalocyanine residue, the benzene nucleus A isunsubstituted or substituted by at least one alkyl group having up to 4carbon atoms and n represents a whole number from 1 to 8.

2. A phthalocyanine pigment mixture as claimed in claim 1 wherein n is 3or 4.

3. A mixture as claimed in claim 3 wherein there is l to 20 percent,based on the total weight of the mixture, of the compound of formula (I)as defined in claim 1. I

4. A mixture comprising 25 parts of copper phthalocyanine in a form and1 part of tris-(benzothiazolylthio-methyl) copper phthalocyanine.

5. A mixture comprising 97.5 percent of copper phthalocyanine in B formand 2.5 percent of tris- (benzothiazolyl-thio-methyl) copperphthalocyanine.

6. A process for the stabilisation of phthalocyanine pigments whichcomprises incorporating therein at least one compound of the formula:

represents a whole number from 1 to 8.

a: a a s: a:

atent No. 3,75%955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONDated August 973 inventor-(s) Jean Andre Paul Kienzle; Michel ErnestAntoine Huille;

and Louis Antoine Cabut It is certified that error appears in theabove-identified patent Sand that said Letters Patent are herebycorrected as shown below:

In the heading insert:

Ugine Kuhlmann, a corporation of France,

[73] Assignee:

Paris, France.

Signed and sealed this 8th day of October 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. Attesting Officer C. MARSHALL DANN Commissioner ofPatents USCOMM'DC 60376-P69 U.S. GOVERNMENT PR NTING OFFICE: I969O-366334 FORM o-1050 (10-69)

2. A phthalocyanine pigment mixture as claimed in claim 1 wherein n is 3or
 4. 3. A mixture as claimed in claim 3 wherein there is 1 to 20percent, based on the total weight of the mixture, of the compound offormula (I) as defined in claim
 1. 4. A mixture comprising 25 parts ofcopper phthalocyanine in Alpha form and 1 part oftris-(benzothiazolyl-thio-methyl) copper phthalocyanine.
 5. A mixturecomprising 97.5 percent of copper phthalocyanine in Beta form and 2.5percent of tris-(benzothiazolyl-thio-methyl) copper phthalocyanine.
 6. Aprocess for the stabilisation of phthalocyanine pigments which comprisesincorporating therein at least one compound of the formula: